Blennies are members of the family Blenniidae of which there are more than 50 genera and over 400 species. Considering how many blennies there are, it’s interesting to note that only a few make their way into the aquarium trade with any frequency. The ones that do make their way into the trade, however, are generally-speaking, excellent marine aquarium animals with a penchant for eating algae. This is good news for marine aquarist, as many blennies good looks means that the aquarist needn’t sacrifice beauty for algae-eating ability. In this article, we take a look at some of our favorite algae-eating blennies from the genus Salarius including the lawnmower blenny (S. fasciatus) and the starry blenny (S. ramosus).

Blennies in General

Most blennies have several traits in common, including, but not limited to, comblike teeth, a continuous dorsal fin, and blunt heads. Most blennies lack scales and a swim bladder. The largest blennies may reach about 54 cm, but most are smaller than 15 cm. All are elongate—almost eel-like—and a few have well developed defense mechanisms such as venomous fangs. Blennies can be found in the Indian, Pacific and Atlantic Oceans primarily in tropical or subtropical water. Usually they are bottom-dwelling fishes and feed on both algae and benthic invertebrates. A few are planktivores, while some actually feed on the skin of other fishes. The family name originates with the Greek word “blennos”, meaning mucus.

The Lawnmower Blenny

The lawnmower blenny—sometimes called the jeweled blenny (Salarias fasciatus)—is a tropical, Indo-Pacific species ranging from the Red Sea and East Africa to Samoa. It can be found in shallow water as far north as the Ryukyu Islands and all the way south to the Great Barrier Reef and New Caledonia. This fish grows to about 14 cm in length and is an excellent algae-eater. In the wild, this species inhabits reef flats and shallow lagoons, as well as seaward reefs and estuaries where it feeds on algae-covered rubble which it scrapes off the substrate. It makes an excellent aquarium species if there is enough green stuff upon which it can feed. Adults of this species can become territorial and somewhat belligerent, especially in a smaller aquarium.

The Other Lawnmower Blennies?

There are several species in the genus Salarias, which make their way into the marine aquarium trade. While they are all commonly called lawnmower blennies and identified to the species level as Salarias fasciatus, in reality, not all lawnmower blennies are the jeweled blenny discussed above. It is likely that many of the larger lawnmower blennies identified as S. fasciatus are in fact another species of Salarias blenny altogether. For example, the seram blenny (S. ceramensis) is commonly mislabeled as S. fasciatus, but the seram blenny has a darker chest and belly than S. fasciatus. The seram blenny is known to be native to the Western Central Pacific including the Philippines, Indonesia and Papua New Guinea. For those eager to positively identify the one from the other when they are not able to be viewed side-by-side, the aquarist can always resort to counting pectoral fin rays. The seram blenny possesses 15 pectoral fin rays, while S. fasciatus has just 14.

The Starry Blenny

The starry blenny (Salarias ramosus) is a tropical species that hails from the Western Central Pacific from the Philippines to northwestern Australia. Growing to about 14 cm, this species, which is also sometimes called the snowflake blenny, is just as good at algae control as the lawnmower blenny, but it is better for smaller tanks because it is smaller than the seram blenny and less aggressive than both of the Salarias species already discussed. Many aquarists also feel the white frills on their heads, numerous pearly spots and yellow pectoral and tail fins make them even more attractive than the lawnmower blenny. In the wild, the starry blenny is frequently found in water up to 15 meters deep around protected inshore reefs and in estuaries. They frequently congregate in small groups in rubble zones on the edge of reefs.